<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>这是div</div>
<input type="text" id="i1">
<input type="button" value="按钮" onclick="f()">

<script>
    function f() {
        let i = document.querySelector("#i1");
        let d = document.querySelector("div");
        d.innerText = i.value;
    }
</script>
</body>
</html>